(a) Field of the Invention
The present invention relates to a panel and a test method for a display device.
(b) Description of Related Art
Recently, flat panel displays such as organic light emitting diode (“OLED”) displays, plasma display panels (“PDPs”), and liquid crystal displays (“LCDs”) have been developed which replace displays employing heavy and large cathode ray tubes (“CRTs”).
PDPs are devices which display characters or images using plasma generated by a gas-discharge. OLED displays are devices which display characters or images by applying an electric field to specific light-emitting organics or high molecule materials. LCDs are devices which display images by applying an electric field to a liquid crystal layer disposed between two panels and regulating the strength of the electric field to adjust a transmittance of light passing through the liquid crystal layer.
Among the flat panel displays, as examples, the LCD and the OLED display each include: a lower panel provided with pixels including switching elements and display signal lines; an upper panel facing the lower panel provided with color filters; and a plurality of circuitry elements.
When the display signal lines become disconnected in the process of manufacturing a display device, the disconnection thereof can be detected via predetermined tests. Such tests include an array test, a visual inspection (VI) test, a gross test, a module test, and so on.
The array test determines the disconnection of the display signal lines by applying predetermined voltages and detecting whether or not output voltages are generated before a mother glass is divided into separate cells. The VI test determines the disconnection of the display signal lines by applying predetermined voltages and viewing the panels after the mother glass is divided into separate cells. The gross test determines image quality and disconnection of the display signal lines by applying predetermined voltages and viewing display states of a screen after the lower panel and upper panel have been combined, but before driving circuits are mounted on the screen. The module test determines an optimum operation of the driving circuits after the driving circuits are mounted on the screen.
Unfortunately, when data lines of the display signal lines are disconnected in the bottom right and bottom left regions of the lower panel, it can be difficult to detect such disconnection using the array test.